I have been using Flex Builder for while, then this just happen, and now it would not launch again.

!SESSION 2009-09-01 11:24:33.517 -----------------------------------------------
eclipse.buildId=unknown
java.version=1.5.0_11
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_US
Command-line arguments:  -os win32 -ws win32 -arch x86

!ENTRY org.eclipse.equinox.app 2009-09-01 11:25:45.449
!MESSAGE Product com.adobe.flexbuilder.standalone.product could not be found.

!ENTRY org.eclipse.osgi 4 0 2009-09-01 11:25:45.464
!MESSAGE Application error
!STACK 1
java.lang.RuntimeException: No application id has been found.
    at org.eclipse.equinox.internal.app.EclipseAppContainer.startDefaultApp(EclipseAppContainer.java:236)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.start(EclipseAppContainer.java:98)
    at org.eclipse.equinox.internal.app.Activator.addingService(Activator.java:112)
    at org.osgi.util.tracker.ServiceTracker$Tracked.trackAdding(ServiceTracker.java:1064)
    at org.osgi.util.tracker.ServiceTracker$Tracked.trackInitialServices(ServiceTracker.java:926)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:330)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:274)
    at org.eclipse.equinox.internal.app.Activator.start(Activator.java:54)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:999)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:993)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:974)
    at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:346)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:260)
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:400)
    at org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:111)
    at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:417)
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:189)
    at org.eclipse.osgi.framework.internal.core.BundleLoader.findLocalClass(BundleLoader.java:340)
    at org.eclipse.osgi.framework.internal.core.SingleSourcePackage.loadClass(SingleSourcePackage.java:37)
    at org.eclipse.osgi.framework.internal.core.BundleLoader.findClassInternal(BundleLoader.java:405)
    at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:369)
    at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:357)
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:83)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClassInternal(Unknown Source)
    at org.eclipse.core.internal.runtime.PlatformActivator.startAppContainer(PlatformActivator.java:47)
    at org.eclipse.core.internal.runtime.PlatformActivator.start(PlatformActivator.java:32)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:999)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:993)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:974)
    at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:346)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:350)
    at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1118)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:634)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:508)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:282)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:468)
    at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:195)
    at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:297)

Has anyone seen this before? Please let me know, thanks.